Generally, a conventional faucet comprises a control valve which is formed inside thereof and is configured to control the on/off operation of water flow and the mixing ratio of cold and hot water. Also, a shell covers around an outer periphery of the control valve and is secured on a faucet body by engaging a first threaded section of the shell with a second threaded section on the faucet body such that the control valve is secured and operated inside the faucet body.
However, conventional faucets are disadvantageous because the faucet body is connected with the shell by engaging the first threaded section with the second threaded section, and an O-ring is disposed therebetween thus achieving the leakproof effect between the control valve and faucet body. Nevertheless, when the shell is pressed by a user, a generated torque force may act on the O-ring which leads to the O-ring being twisted, deformed or further leads to breakage and leakage of the faucet. Moreover, when the leakage happened, the user needs to replace the O-ring which cannot definitely prevent the control valve from leakage again. In conclusion, the conventional faucet is insufficient in the strength of structure and the leakproof effect. Therefore, there remains a need for a new and improved design for a control valve for faucet to overcome the problems presented above.